The present invention relates to a porcelain composition of a Pb(Mg 1/3, Nb 2/3)O.sub.3, - PbTiO.sub.3 - Pb(Mn 1/3, Nb 2/3)O.sub.3 system having a high dielectric constant and being used as a laminated porcelain condenser or the like. The present invention is also directed to a method of reducing the sintering temperature of such a high dielectric porcelain composition.
Conventional porcelain dielectrics of a Pb(Mg 1/3, Nb 2/3)O.sub.3 - PbTiO.sub.3 - Pb(Mn 1/3, Nb 2/3)O.sub.3 system had excellent electrical properties, having relatively high dielectric constants .epsilon..sub.s, extremely small dielectric loss tan .delta., and large insulating resistance IR. However these porcelain dielectrics required a range of temperatures greater than 1150.degree. C. for the sintering thereof.
Accordingly, a large amount of heat energy was required for the sintering process. Furthermore, there was a tremendous deterioration and loss of material forming the sintering or burning furnace at high temperatures, thereby causing the maintenance cost of the burning unit to be high.
In addition, it is necessary in the case of laminated porcelain condensers, for the porcelain dielectrics to be sintered with the internal electrodes embedded therein, Ag - Pd alloy being generally used as the internal electrodes. As the temperature under which the dielectrics are sintered increases, the amount of Pd must also be increased. Accordingly, the Ag - Pd alloy which is used for the internal electrodes becomes expensive, making the cost of production high.